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Heating Element Control
CharcoalRoaster
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Posted on 01/04/2021 8:12 AM
So I finally figured out my airflow issue that caused 3 separate heating elements to fail and melt into oblivion = too much ceramic insulation! I was so worried about the element shorting that I put too much around the coils and they apparently weren't getting enough airflow. Problem solved ThumbsUp

I did a test roast of 600g and everything went smooth except for controlling the heating element. In order to test the airflow I just hooked it up to a basic on/off switch. However, with 240v/30a of juice running through that bad boy I hit FC in like 7min. The resulting cup isn't bad but I need/want to control that amount of heating power moving forward.

I tried looking around but couldn't find a solid solution so I'll throw it out the question again -- what are my options for heating element control?

(I have a number of components like Arduino/TC4, ZCD, Random Fire SSR, etc lying around if that helps)

Thanks everyone!
 
CharcoalRoaster
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Posted on 01/05/2021 9:20 AM
The elements I bought came with stock thermistors - I threw them out but would they be useful in any type of controller setup?
 
renatoa
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Posted on 01/05/2021 9:30 AM
What heating element(s?) are you talking about ?
Is it a single wire unit, or multiple wires in parallel ?
If double elements, I would consider to have one permanently on, and control only the second, thus half current to handle, much easier to control 15 instead 30 Amps...more options...
If single element, then a 40 Amps SSR on a massive heatsink, and TC4. True 40 amps, beware of counterfeits !
 
CharcoalRoaster
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Posted on 01/05/2021 10:00 AM
https://mccombssu...ps2162280/

Here's the element I'm running Renatoa in a very simple setup - direct connection to a 30a outlet through a single pole switch - basic on/off capabilities.
 
renatoa
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Posted on 01/05/2021 10:38 AM
Heavy metal... Grin

Single wire running through four elements in series.
So SSR + TC4 seems the most straightforward.
Or, for the brave enough full manual style fans, such variator:
https://www.amazo...B07H6BFZRG
 
jkoll42
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Posted on 01/05/2021 10:54 AM
The temporary you can do just to be sure your overall design is good to go is what I did decades ago on my first popper mod..... manually turn on/off the power switch during the roast. Yes it's annoying to flip it on for a few seconds and off for a second but it will get you by until you do a TC4/SSR like renatoa said.... or drop a grand on a giant variac smile
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
CharcoalRoaster
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Posted on 01/05/2021 11:05 AM
I mean, since I have all the necessary TC4 components I would prefer to go that route -- however I wasn't having any luck wiring it up last time so any wiring diagrams/suggestions would be invaluable.
 
renatoa
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Posted on 01/05/2021 3:19 PM
You could start with TC4 for measurement and logging, and manual power control with the $20 variator.
Then try to add the power control to TC4, having the variator as a backup plan if anything fails.
 
CharcoalRoaster
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Posted on 01/05/2021 7:55 PM
Good point - just ordered!
 
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